


in his skin

by timkons



Category: Haikyuu!!
Genre: Alternate Universe - Akaashi is a tentacle alien, Alternate Universe - Aliens, Alternate Universe - Apocalypse, Body Horror, Established Relationship, Explicit Sexual Content, M/M, Mildly Dubious Consent, OT4, Polyamory, Porn With Plot, Tentacle Monsters, Tentacle Sex, Tentacles
Language: English
Status: Completed
Published: 2017-07-11
Updated: 2017-07-11
Packaged: 2018-12-01 00:13:49
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,207
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11474571
Author URL: https://archiveofourown.org/users/timkons/pseuds/timkons
Summary: Kenma and his boyfriends fuck a tentacle prince to save Earth from an alien invasion.





	in his skin

****When the sky falls and lights up like the Northern Lights, Kenma’s the one that turns to his two boyfriends, face alight with the glow of the green and purple swirling in the sky, and says, “I was right.”

Mothers are screaming for their children and the newly installed national alarms blare when the ships make contact and begin to pierce the crust of the earth, but all Bokuto or Kuroo can hear over the strums of breaking glass and cracking cement is Kenma’s quiet vow, “we’re going to survive this.”

-

Against Bokuto’s insistence, they don’t go to quarantine. “Quarantine is where they gather everybody to die,” Kenma explains, and that is that. They grab non-perishables, a can opener, and two broken pipes for defense at Kenma’s direction as they make their way out of the city, grabbing as much medicine and food that hasn’t been raided already.

It’s a long five way trek in the woods and Bokuto mopes about it the whole way -- until they hear the gunshots and watch the city get torched by the men in white space suits. From their perch in the makeshift treehouse they spent two days making, they watch their home and the life they knew go ablaze. Bokuto cries enough for all three of them, and Kuroo and Kenma hold him tight, even when his throat goes dry and his crying sounds like nothing more than the heaves one lets out when there’s nothing left to puke.

Kenma looks up to the tie-dye sky that started to glitter two nights ago, and closes his eyes. “The wind is blowing south. We can’t stay here.”

-

Kenma declares that the forest is safest and that they need to make it to the shore.

“The port would have been quicker,” Kuroo complains, but Kenma shakes his head.

“No. Any boats leaving from the port would have been inspected and quarantined. We needs to find something smaller, something that can go under the radar.”

“Kenma wasn’t wrong about the city, so he’s probably right about this too. We’ll survive it,” Bokuto assures, patting Kuroo heartily on the back and kissing his boyfriends’ cheeks, one after the other. Bokuto’s spirits remain high, even when their legs start to hurt and Kuroo’s hair goes flat from not having any pillows to prop against his face and even Kenma starts to doubt himself.

-

The first body they encounter belongs to a nameless subordinate of the Ministry of Defense. They can’t tell if it’s a man or a woman, and they don’t care to find out. Even before Bokuto toes the corpse, they know it to be dead. The body lays face down, but the head is twisted up, and the mask of the safety suit has been cracked open. A few forest bugs are crawling around the raw gore of brain and bone that still smells fresh.

Bokuto makes a face and pulls Kuroo’s sleeve. “C-Can we go? This is freaking me out.”

“We should inspect the body,” Kenma says, kneeling down and grabbing a stick to prod at the corpse. The stick sizzles upon contact with the body and Kenma lifts it, a thick drop of silky green liquid falling off. It melts both the point of the stick and everything it touches. Kenma winces.

“Looks like lube,” Kuroo jokes.

“Stop fuckin’ around!” Bokuto screeches and he punches Kuroo in the shoulder.

“I’m trying to lighten the mood!”

Kenma tosses the stick away, burrowing his face in his knees. Kuroo and Bokuto are both scared, he can tell from their bickering, but they trust him. This isn’t like a video game where there’s a reset button, but Kenma’s not sure he knows how to win against this boss battle. “We need to get to the water as soon as possible.”

-

They encounter their first alien a week later. It walks like snail, burning everything in its wake with the venomous slime that leaves its body, and they learn for the first time that the blobs whip out tentacles used to fight. One of those very such tentacles reaches out for them and continues to stretch toward them, even as they run away. Bokuto trips on a root and Kuroo hauls him up while telling Kenma to run, but it’s no good; the three of them end up clinging to each other, backed against a tree trunk, as the tentacle inches forward, the poisonous liquid dripping and sizzling as it approaches.

“Stab it with the pipes,” Kenma breathes, and both Kuroo and Bokuto wield the pipes they’ve been carrying for weeks.

They lose both lead pipes from trying to pierce the gelatinous body, but the alien merely sucks the pipes in, its skin becoming hard like lead. Kenma grips either of his boyfriend’s hands as if this is the end, but the tentacle slowly halt to a standstill, the lead becoming solid and less flexible in the passing seconds.

All three of them are backed against a tree trunk, breathing heavily and staring at the tentacle now made of lead that’s hovering above them.

“Kenma was right again!” Bokuto says cheerily. Kuroo starts bickering with him him and Kenma sighs.

\-  

They following the never-ending tentacle to the body’s root and stare. There’s no defining features, all smooth and dirty, just like the pipe. Kenma circles around it and frowns. “It takes on the quality of whatever it absorbs.”

“What would happen if it absorbed a human?” Bokuto asks, peeking over Kenma’s shoulder.

“Let’s not find out.”

Before anybody can stop him, Bokuto reaches out and pokes the tentacle. Kenma pinches Bokuto’s ear hard, but Kuroo beats him to it, slapping Bokuto upside the head. “Idiot! What if it would have absorbed  _you?”_

Kenma lets out an unsteady breath as they fight. Idiotic or not, Bokuto’s simplicity proves one thing: the aliens only absorb the first thing they touch. Kenma breathes a bit easier, knowing they can use this to their advantage.

-

Kuroo and Bokuto spoon him on either side on the night their food runs out. They’re only a day’s trip away from the sea, from getting away from all this insanity, and Kenma should feel relaxed and ease.

He doesn’t. Eyes peeled open as his boyfriends snore against his ear, he watches as the sky now swirls in a beautiful rainbow. Like the music that signals an upcoming boss battle, Kenma can’t help but feel that the worst’s about to come.

-

The worst comes as they’re lapping around the last waterfall before reaching the city. Kuroo and Kenma are both exhausted, and so is Bokuto, though he’s loudly prancing around as though what energy he shows might infect his boyfriends. Kuroo’s smiles lazily and Kenma leans against him, Bokuto entirely too infectious to be ignored, until Bokuto spreads his arms back and pushes back on their chests, holding them behind him.

“What the hell, bro?” Kuroo asks, but Kenma slaps his palm over Kuroo’s mouth, eyes wide and focused on the alien, this one a dark emerald green, bent over the pool of water at the waterfall’s base. It’s as still as Bokuto, but Kenma can tell Bokuto’s scared because Kenma can hear his heart beating.

It seems like forever before the alien pushes upward, completely still and erect. Kenma almost thinks the alien might not move until they move, but then it twists. Or rather, it doesn’t so much as twist as it does rotate, still completely tall and still.

“I think it found us,” Kuroo breathes, and no sooner than said, the alien blob lurches forward and slithers closer, this one much faster than the previous alien they encountered.

“G-Guys? I don’t have anything to fight with,” Bokuto nearly cries out, and there’s no time to run, not for Bokuto, though Kenma screams and tries to reach out for him as Kuroo grabs Kenma in both arms and pulls back.

The alien mauls Bokuto, a sight so gruesome that even Kuroo freezes in place. Kenma watches helplessly as the alien seems to flatten against Bokuto, pinning down his legs and arms and slowly beginning to spread around his neck.

“Get out of here,” Bokuto pleas, the shimmer of color that’s now visible in the sky even during daylight reflecting off his eyeballs. “Please live! Just leave m--”

Bokuto doesn’t get to finish his sentence because the alien goo finds its way into Bokuto’s mouth and presses in, gagging Bokuto on his own words. Kuroo screams and Kenma feels body go limp. He can’t tell if it’s him or Kuroo that’s shaking more as they watch Bokuto clench his eyes and futilely try to clamp his mouth on the alien substance. Kuroo’s still holding Kenma when he falls to the ground, beginning to sob as their boyfriend’s body gets violated by an alien.

“T-Tetsu, calm down,” Kenma insists, shakily breaking out of his boyfriend’s considerably weaker grip. “Look, he’s not dying. He’s not-- Whatever it is, it’s not killing him.”

Kenma crawls over on all fours to Bokuto, where he’s crying just like Kuroo, and pets his hair gently as the alien begins to change. Bokuto starts coughs just as the form rises in a recognizably human one, still glistening green in the sunlight as the form settles. When the tentacle pulls out of Bokuto’s mouth, it’s a formed hand attached to a very familiar bicep.

“Hey, hey, hey!” the alien, now a perfect replica of Bokuto, says. Both Kuroo and Bokuto pass out on the spot.

-

“This is creepy. Can we do anything about his face?” Kuroo asks that night, around the fire they’ve built. They have fresh fish roasting over the fire on handmade skewers, and it would almost feel like a summer camp trip if not for Bokuto’s identical clone sitting next to him.

“Don’t say it’s creepy! It’s a good face!” Bokuto yells, and the alien merely nods, eyes bright in that arrogant kind of way Bokuto only gets on the court.

 _“Your_  face is a good face.  _That_ face is just freaky,” Kuroo clarifies. He’s sitting on the opposite side of the alien, not as convinced as obviously Kenma or Bokuto are.

“It’s just for now,” the alien says. “If you let me taste your essence, I can make a form that’s a conglomeration of all three of you.”

Kuroo flips over their fish, still glaring. “And what way would that be?”

The alien shrugs in the way Kenma’s seen Bokuto do thousands of times before, it feels uncomfortable. “Let me feel your organisms.”

“Nuh uh! You’re not crawling down my throat and suffocating me with your freaky tentacles!” Kuroo yells, wielding a skewer as though it were a sufficient weapon against the alien.

“Actually, it wasn’t that bad. It kinda felt good,” Bokuto admits with a blush. The alien smirks cockily at him and Bokuto flushes further, looking away. “N-Not saying I’d do it again!”

“Any orifice will do,” the alien clarifies. Kuroo chokes and Bokuto hums as if he’s actually thinking about it.

“How do you know that’s what will happen?” is Kenma’s only question.

At the same time, both Bokuto and the alien turn to him with the same, small frown prompting further explanation. Kenma tries his best not to be freaked out.

“The last alien we encountered didn’t change forms when we touched it again,” Kenma explains. He feels uncomfortable beneath all the attention and prods a skewer against the fish like Kuroo was doing. “So how do you know you would be able to?”

“I’m Akaashi, fiftieth-fourth prince of the third Fukuroudani Empire and leader of this expedition. There’s a lot that I can do that my army cannot,” the clone Bokuto says. “I know I can do it, just open your essence up to me.” 

Bokuto nods encouragingly, and Kenma and Kuroo both glare at him. “Why should we trust you?”

“Because he looks like me, duh,” Bokuto says proudly.

Kuroo shakes his head. “No, I mean, if you’re the one responsible for invading our damn planet, why the hell should we trust you, let alone  _help_ you?”

Akaashi straightens up. “I can’t convince you to do anything you do not wish to, and I have no evidence to prove it, but I can help you reclaim your planet. This was meant to be a peaceful mission with the sole intention of making contact with your species, but I was overthrown. Luckily, I survived. I believe with my help, you can overthrow my general, I can reclaim my army, and we can coexist peacefully.”

“By ruling us?” Kuroo snarls sharply 

“Is that your plan, Akaashi? Are you going to rule us?” Bokuto asks, shocked.

Akaashi, though with Bokuto’s face, shakes his head. “Of course not. If anything, my kind would assimilate to yours, as we always have. You wouldn’t even know we walk among you. My general is incredibly greedy, but that is not our way. 

Kenma bites his bottom lip and considers the options. It’s about the sketchiest offer he’s ever heard, but it’s also an unheard of opportunity. For the first time since the spaceships landed, Kenma feels like there might be hope. “You can guarantee you’ll get your army under control?”

“Yes,” the Bokuto lookalike says, eyes set in that serious, sincere way Kenma knows all too well. 

“Kenma, you’re not really considering--”

“We should do it,” Kenma says, heart thumping. Sleeping with the strange creature was always the most fun option in games anyway. 

-

“Kenma, please don’t do this,” Kuroo begs.

Kenma spares one glance before laying his clothes down on a patch of soft leaves he and Bokuto gathered earlier. Naked and freshly watched in the waterfall, he lays himself down and breathes. “I’m not asking for your permission. And Bokuto says it feels good.”

Bokuto -- the real Bokuto -- shamelessly nods from where he’s sitting on a log. The other Bokuto is kneeling between Kenma’s spread thighs, eye alight by the fire as Kenma knows well from many nights of pleasure.

“You should listen to your boyfriend,” the alien says pointedly. “This is the only way if you want to save your world. This form is pleasing enough for the both of you, isn’t it? Unless you find your other boyfriend unattractive, there should be no problem.”

Bokuto screams that Kuroo better think he’s hot at the same time Kuroo squawks that it’s completely different even if the alien looks exactly like Bokuto, but Kenma’s staring, trying to put the pieces together. “How do you know we’re boyfriends? 

“Because I inherit all the memories and sensations of my host.”

“Their essence.”

Akaashi nods. “We must hurry.”

Kenma takes a deep breath and relaxes. “Okay.”

“Kenma!” 

“It’s kinda hot watching me fuck Kenma,” Bokuto says, already pulling his dick out.

“You’re gonna jerk off now?” Kuroo howls.

Bokuto shrugs. “I mean, if I don’t have anything better to do and I’m watchin’ anyway.” 

Kuroo rolls his eyes, and he catches Kenma’s eye. Kenma’s watching him as a form that’s all too familiar yet completely alien settles on him, looking for a bit of comfort. Kuroo’s face looks devastated but he creeps close, petting Kenma’s hair. “It’s going to be okay, Kenma.”

“I know,” he says bluntly and Kuroo coughs on a laugh.

“I’m going to begin,” Akaashi says, and he pushes up, just enough for Kenma and Kuroo to both watch in horror as what was Bokuto’s dick seconds ago begins to morph into a tentacle, not unlike the one that tried to attack them or the one that crawled down Bokuto’s throat.

“Hey, move outta the way so I can see!” Bokuto whines.

Kuroo’s breathing heavily and clutching Kenma’s hand just as hard. “Just…don’t hurt him. Please.”

“I won’t,” Akaashi promises, the tentacle settling on Kenma’s thigh when it gets too long and slithering up Kenma’s thigh in back and forth motions. The ooze it leaves behind is warm and tingles, leaving Kenma’s skin a patch of prickled skin in its wake. Kenma finds himself moaning and arching against the tentacle before it even enters him, thighs spreading.

Oddly, it’s Kuroo who speaks first. “Kou. C’mere and look at this.”

Bokuto scrambles over, the brittle leaves crunching beneath his shoes. He gasps watching the tentacle slither around the base of Kenma’s cock and loop down his balls right into Kenma’s ass. Kenma chokes as the heat and wetness caress his genitals, the tentacle lightly pulsing against his skin. It’s unlike anything he’s ever experienced, the tip of the tentacle slipping inside of him and expanding as his body allows.

Besides the call of a bird, the only sounds are Kenma’s increasingly rapid breath and the slap of Bokuto’s fist against his balls as he aggressively jerks himself. Without prompting, Akaashi offers a hand, his fingernails dripping into small tentacles coated with the same ooze coating the inside of Kenma’s ass and swirling up and down his cock. “Oh, _shiiiit…”_

Kenma hums in agreement, practically riding the tentacle wrapping around him as Bokuto thrusts in time, as though it were Bokuto fucking him instead of the slick tentacle now pushing in wavelike motions inside of him. Kenma’s back arches and he sighs softly, Bokuto grunting back as he fucks into the offered tentacles happily. It’s not all he does, stroking at the underside of the tentacle and murmuring incoherent little nothings about how good it feels, how he needs more, and fuck, fuck,  _fuck._

Akaashi doesn’t move, still kneeled between Kenma. His eyes flicker between Kenma and Bokuto, letting his tentacles do all the work of thrusting and moving even as he remains still, observant. “Your boyfriends are beautiful.”

Kuroo looks up, eyes suddenly wide and his throat dry. Akaashi licks his lips and leans forward. He still looks like Bokuto and Kuroo can’t say he doesn’t understand what Bokuto meant earlier about jerking off. He can feel his dick giving a tug, as much as he doesn’t want to give into it, his entire body getting hot with that heat that starts low in his stomach. “Y-Yeah, they are.”

“Feels good,” Kenma sighs. He twists his head toward Kuroo and yanks on his hand pointedly, and Kuroo leans down for a kiss. Kenma’s lips are warm, soft, and wet, and Kenma holds both of his cheeks to kiss deeply. Kuroo can feel the tentacles fucking him from the inside, stuttering Kenma’s breaths, and grabs at Kenma’s chest to cup the soft warmth and pinch his nipples, which only makes the younger boy moan into his mouth. Kuroo feels Kenma’s sweet vibrations tingle all the way to his tailbone.

Bokuto’s quick to get jealous, yanking at Kuroo’s waist to pull him closer, tugging him up to kiss him hard and needily. His tongue presses into Kuroo’s mouth, greedily lapping and tasting in that unfocused, overwhelming way that Kuroo loves so much. Kuroo grins against Bokuto’s lips, kissing him back even as he feels the thrust of his dick and the heat of Akaashi’s swirling tentacle against his leg.

 _“Hnngh,”_  Bokuto whines in a high-pitched voice as Kenma moans and yanks at Kuroo’s hand again.

“You should do it,” Kenma gasps, watching Bokuto and Kuroo kiss with reckless abandon. “It feels good, Tetsu. It’s so hot inside. Soft and--”

“Wet,” Akaashi finishes, Kenma cut off by a loud scream when he shifts his tentacle into something with more girth and texture, perfect for hitting the prostate.

“I-I,” Kuroo begins over and over, unable to finish at the way Kenma throws his head back, lips parted, and sighs so deliciously obscene, his legs bending and curling into the forest ground, hips grinding and clenching on the tentacle inside him. How is Kuroo supposed to say no to a sight like  _that?_ “I could try…”

With the free hand Akaashi has placed rubbing gentle circles on Kenma’s knee, he beckons Kuroo forward, and Bokuto grunts out a soft whine when Kuroo’s mouth collides with Akaashi’s. The first thing he notices is the overwhelming heat, the way Akaashi’s mouth seems to radiate warmth. At the first slide of his tongue against Kuroo’s bottom lip, he finds himself opening his mouth to Akaashi, velvety tongue sliding around his as it makes its way to the back of his throat.

Kuroo gives a jolt and his eyes open wide when he realizes that Akaashi’s tongue keeps going and going, and when it’s midway in his throat, he realizes that it’s another of his tentacles, even as the alien continues to kiss him through the tentacle’s exploration. The tentacle feels hot like Bokuto’s tongue when he’s kissing Kuroo and wants attention, but as the tentacle takes on a texture as as it slides down his throat, Kuroo tastes and feels Kenma’s delicate tastebuds.

It’s a bit uncomfortable, but Kenma pets his hand and Bokuto squeezes his shoulder in reassurance, and the most bizarre thing of it all is that as Akaashi’s tentacle explores his body, he can feel Kenma and Bokuto as well. It’s like it’s his hand reaching out for Kenma or his palm clapping Bokuto’s shoulders, his dick and ass both suddenly experiencing the same movements Kenma and Bokuto are firsthand. Kuroo’s eyes slide back into his head, unable to do much more than drool on the tentacle slotted in his mouth or buck against the friction that isn’t truly caressing his body.

Kenma fists his cock and begins to slide the pliant tentacle up and down his cock, the loose loop around his balls growing tighter as he does, and Akaashi’s tentacle around Bokuto’s cock splits off to slither inside his urethra. Bokuto let’s out a full bodied moan that makes Kuroo’s entire body shake, the warmth of Bokuto’s voice in his throat although he can’t speak. He’s shivering like Kenma as he quickly slides toward his orgasm, Kuroo realizes, but more than that, it’s the clenching of his eyes, the thrust of his hips, the prying of his ribs as if they’re about to open to the gates of something pleasurable and unknown, and he realizes  _that’s Akaashi_.

Akaashi’s lips move against his a final time before he’s pulling back, tentacle still lodged in Kuroo’s throat, but Akaashi no longer looks like Bokuto. Instead it’s eyes glistening like emeralds from the fire looking back at him, pale skin and soft dark locks, tumbling around his face. Akaashi smirks as Kuroo gags, watching the muscles in Kenma’s body clench and Bokuto’s breathing get heavier. Akaashi remains ever still even as his tentacles begin to rapidly thrust against Kuroo’s boyfriends in time, building the sensations within Kuroo.

Akaashi closes his eyes and Kuroo feels the sensation of Akaashi tilting his head back and sighing in pleasure as he sinks inside both Kenma and Bokuto. In this vision, Akaashi’s pistoning inside them both at once, their thighs wet from the slide of the tentacles, doing their everything to get more of that flexible heat. Akaashi’s head snaps forward and his eyes widen as Kenma, Bokuto, and Kuroo all straighten tight with release, and the three of them messily come on themselves, Kuroo’s body spasming impromptuly from a threefold orgasm. His head feels like it’s exploded and ascended into the clouds, his entire body feeling like nebulous glitter. He can’t feel anything now, only the sweet twist in his stomach as if he’s free falling.

Kuroo lets out a loud shudder, the tentacle falling limp out of his mouth as he finally remembers to  _breathe_ , and Kenma heaves heavily as the tentacle tightens around the base of his cock, though neither are like Bokuto, who’s glaring despite the obviously strong orgasm he had. “Akaashi, it’s not enough.”

The alien cocks his head to the side, as though both confused and amused by this revelation. “Not enough?”

“Kou’s insatiable,” Kuroo explains, wiping his mouth of the cloy ooze still on his lips.

“Want you inside me again,” Bokuto says a bit cheekily, blushing as he wiggles his hips pointedly.

“Tetsu too,” Kenma whispers after he regains his breathing and stops writhing against the wet patch of his clothes and leaves. “We need to…for earth.”

Kuroo snorts. “Sure, that’s the only reason why you want me to do this.”

Kenma grins a bit tiredly and doesn’t disagree. “Maybe I have another reason.”

“Please, Akaashi, just  _fuck me!”_  Bokuto begs, still thrusting his limp cock into Akaashi’s receding tentacles. Bokuto holding onto to the tentacle to stop it from leaving.  _“Pleeeaaase.”_

“I think it’s Kuroo-san’s turn now,” Akaashi says a bit fondly, “but how about we kiss?”

-

“Can we keep him?” Bokuto asks, once they’re all naked and laying side-by-side. He has a leg propped over Akaashi’s thigh and keeps nuzzling at Akaashi’s neck while begging for another another tentacle. “I mean, after all this is all over. Do you want to stay with us, Akaashi?”

“I wouldn’t be opposed,” he says, now in the voice and likeness of his individual form. His smile is soft and his eyes are sharp, and the only people as beautiful as Akaashi are Kuroo’s two boyfriends.

“Guess we have no choice,” Kuroo sighs, spooning Kenma’s back but letting his hands roam Akaashi’s chest. “What do you think, Kenma?”

“Yes,” Kenma says, in a tone of finality. “We’re keeping him.”

**Author's Note:**

> feel free to hmu on [tumblr](https://90stimkon.tumblr.com/) or [twitter](https://twitter.com/cloneboys), or [consider commissioning me](https://90stimkon.tumblr.com/post/162750545663/commission-me)!


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